Untersuchungen an Nickeloxid-Mischkatalysatoren. XVI. Reduktionsverhalten amorpher NiO?Al2O3/SiO2-Katalysatoren

Studies on Nickel Oxide Mixed Catalysts. XVI. Reduction Behaviour of Amorphous NiO? Al₂O₃/SiO₂ Catalysts The reduction behaviour of NiO? Al₂O₃/SiO₂ catalysts prepared by precipitationdeposition is influenced by the phase composition (amorphous nickel layersilicates and nickel alumino layersilicates, nickel spinels, nickel oxide) and the differences of the composition between surface and bulk. TPR measurements, determinations of the reduction degree, and the nickel particle sizes by static magnetic measurements showed that the reducibility of the NiO? Al₂O₃/SiO₂ catalysts is enhanced and the nickel dispersity is decreased at low Al₂O₃ contents. The decrease of the reducibility at Al₂O₃ contents >5 mole% is caused by the formation of nickel spinels and the decrease of the Ni^II ion surface concentration.